7. Symphyotrichum pygmaeum (Lindley) Brouillet & S. Selliah, Sida. 21: 1635. 2005.
Aster pygmaeus Lindley in W. J. Hooker, Fl. Bor.-Amer. 2: 6. 1834; A. sibiricus Linnaeus subsp. pygmaeus (Lindley) Á. Löve & D. Löve; A. sibiricus var. pygmaeus (Lindley) Cody; Eurybia pygmaea (Lindley) G. L. Nesom
Perennials 1.5–15 cm, cespitose; with short, branched caudices, long-rhizomatous (both wiry). Stems 1–10+, decumbent to ascending (purple), sparsely or densely villous to woolly distally. Leaves firm, margins usually entire, sometimes remotely pauci-serrulate, sparsely villoso-ciliate, apices obtuse to acute, sometimes mucronate; basal often withering by flowering, petiolate (petioles widely winged, sheathing), blades spatulate, 5–19 × 2–4 mm, bases attenuate, apices rounded, faces glabrous or sparsely villous proximally; proximal sessile, blades lanceolate to oblong-lanceolate or (sometimes) -spatulate, 30–50 × 3–10 mm, bases ± clasping, apices obtuse to acute, faces glabrous or sparsely villous; distal sessile, blades lanceolate to oblong, 13–19 × 2–4.5 mm, bases clasping to cuneate, apices acute to obtuse, faces sparsely woolly, sometimes sparsely stipitate-glandular. Heads borne singly. Peduncles densely villous to lanate distally, bracts 0. Involucres hemispherico-campanulate, 9–12.5 mm. Phyllaries in 3–4 series (dark purple), lance-oblong or oblong (outer) to linear-lanceolate or sometimes linear (inner), subequal, outer ± herbaceous, bases not indurate, margins herbaceous (outer) to narrowly scarious and erose proximally (inner), strongly purple, villoso-ciliate in green portion, green zones (inner) 1 / 2 – 2 / 3 of distal portions, apices acute to acuminate, inner sometimes apiculate, appressed to loose and squarrose (particularly outer), faces woolly to densely villous, sparsely to moderately stipitate-glandular. Ray florets 16–28; corollas purple to violet, laminae 12–18 × 2–3.2 mm. Disc florets 53–55; corollas yellow, 5.6–6.5 mm, throats funnelform, lobes triangular, 0.5–0.8 mm (red or white clavate-hairy). Cypselae fusiform to cylindro-obconic, ± compressed, [size unknown], 4–7-nerved (faint), faces ± densely strigillose; pappi whitish to yellowish, 5–7.2 mm.
Flowering summer. Open, active, moist sand dunes, sandy or silty stream banks and terraces, usually cyclically disturbed gravelly tundra and tundra slopes; of conservation concern; 0–200+ m; N.W.T., Nunavut; Alaska.
Symphyotrichum pygmaeum has long been included within or associated with Eurybia sibirica. Though similar in appearance, the two species can be distinguished by the glands present on S. pygmaeum on the distal leaves and phyllaries.